Method of synthesizing sulphurbearing, high molecular weight hydrocarbons



'taining, bodies.

enema Apr. 15, 1941 UNITED STATES PATENT OFF l azaaaso V srn'rnnsrzmo sunrnuno. nron morncumn wnron'r METHOD OF BEABIN HYDROCARBONS Lloyd 1.. Davis, Bert n. Lincoln, and Gordon D.

Byrkit, Ponca City, Okla... asslgnors to Continental Oil Company, Ponca City, Okla, a cor poration of Delaware No Drawing. Application May 2, 1938, Serial No. 205,530

2 Claims. (Cl. 260-609) method for synthesizing relatively, pure high molecular weight sulphur compounds from petroleum hydrocarbons.

Another object of ourinvention is to provide a method for converting petroleum fractions and similar hydrocarbons of low value into high molecular weight sulphur compounds of "great commercial value.

A further object of our invention is to provide a method of synthesizing high molecular weight sulphur compounds from parailln hydrocarbons.

Other and further objects of our invention willappear from the following description.

In accordancewith our invention, it is now possible to prepare relatively pure sulphur derivatives of the higher paraflin hydrocarbons without being mixed with other sulphur-con- We first prepare a relatively pure mono-; di-, or trihalogenated paramn hydrocarbon, free from unhalogenated hydrocar- -bn and from each other. and convert these relatively pure halogenated hydrocarbons by chemical means into sulphur-containing derivatives.

In theprior art. references are made to monochloro paraflin, dichloro parai'iln, trichloro and the like usually considering the product of direct chlorination to be the compound represented by the total chlorine content and therefore the desired compounds. We have found that these materials are very crude mixtures of the chlorinated hydrocarbons and con. taln unchlorinated' hydrocarbons and the mono-, di-, and polychloro derivatives and cannotbe considered the desired ccmpoimds. For ex' very closelytn the percentage oi chlorine in the titles of monoand dichloro waxes, as well as trichloro wax and more highly chlorinated waxes. Its use would not give the same results as a trichloro paramn free of higher and lower chlorinated paraffin.

Even though the appropriate amount of chicrine is introduced in the wax to form a monochloro wax, we have found that the crude chlorination mixture contains, in addition to small amounts of chlorine and hydrogen chloride and the desired monochlor wax, also unchlori'nated wax and more highly chlorinated and less highcule; (3)

percent chlorine respectively.

ampla'a so called "trichloro parafiin' wax" containing 24 percentchlorine. which corresponds trichlorc compound. was separated by means of crystaiiizaticn'from soluble) portion consisted of a mixture of" monochlorowaxaadunchlorinatedwax. Theper; centage of .unchlorinated wax in. the original mixture was-found to be 7.2 percent, Thus.

-ccetone. The first (least.

1y chlorinated waxes.

In contrast to the use of such a mixture, we

have found it possible, as fully described below,

to obtain a relatively pure monochlor compound free from unchlorinated hydrocarbon and free carbons and monohalogenated hydrocarbons, as

well as'from halogenated hydrocarbons containing more than two atoms of halogen per moletrihalogenated' hydrocarbons free from halogenated hydrocarbons'containing' fewer or more than three halogen atoms per molecule and ifreev from unhalogenated hydrocarbons. We refer in this specification. to these materials as'relatively pure monohalogen compounds, 'relatively pure dihalog en compounds, etc. I

We proved the homogeneity of our relatively pure monochlor wax, for example,,by chilling until approximately half of the material had solidified. Solid and, liquid portions were separated by filtration and contained 12.1 and 11.4 Our monochloro wax' is therefore free from both unchlorinated waxand more-highly chlorinated W8,X., Similarly. we may prepare according to our invention diand polychloro waxes free from unchlorinated wax and monochlor wax, as well as from more highly chlorinated waxes.

1 detail-for the manufacture of relatively pure :chlorlnated 'wax are applicable to themanu'faceven'a "triechloro parailin" as ao-caiied inthe prior art because of the total chlorine content,

wasinfacta emlxturecontainingasmuch as 7.2 percent of unchlorlnated quanture of chlorine derivatives o fthe paramn hydrocarbonsof higher and lowerymolecular weight than that represented ;by the commonly known paraiiln wax. including all those paraillnhy-, drocarbons whose monochloro'derivatives melt lower than the hydrocarbons themselves; The chlorination of most petroleum The same methods as are described-herein Q waxes are largely liquids, while the unchlorinated waxes are largely solid. The temperature for the pressing operation will depend, of course, on the character of the wax used initially and will vary considerably depending on this factor. For example, at a temperature of from 80 F. to 90 F.

the monochloro product formed by the chlorina tion of wax having a melting point of 120 F. will be liquid, while the unchlorinated wax will be solid, enabling a ready separation to be effected.

Other methods of separation, as for example, sweating, selective solvent extraction at varying temperatures and the like, may be employed for separating solid unchlorinated wax from chlorinated portions, and for separating the monochloro wax from the more highly chlorinated portions.

The -unchlorinated wax separated from the crudachlorination mixture may be'.recycled to obtainfurther quantities of chlorinated waxes. It does not represent refractory material, and the same proportions'of chlorination products are obtained from it as from, fresh wax.

The liquid chlorinated waxes consist largely of monochloro and dichloro waxes when approximately or 20 percent chlorine respectively is introduced into a starting wax of, say, from 115 to 130 F, melting point, may be present. These monoand dichloro waxes may besseparated from each other bycrystallization from acetone, using about 12 /2. gal;- lons of acetone per 100 pounds of crude chlorinated waxes. In preparing the-solution, an 'elevated temperature is employed to insure that the 'chloro waxes are completely dissolved in the solv vent. The solution is then chilled to a temperature of between minus 15 F. to minus F.

when a paraffin wax of 115 to 130 F. melting P int is used for the initial chlorination. The

but some polychloro wax may be separated into unchlorinated wax, monochloro wax, dichloro, and polychloro wax. It is to be understood, of course, that the separation conditions will vary depending upon the melting point of the starting material.

I In preparing monochloro wax, for example, the separated monochloro wax will be found to contain approximately the theoretical chlorine content. In the case of the wax which had the 120 F. melting point, batches showed chlorine contents of 10.2 percent, 10.5 percent, 10- Percent, and 10.8 percent. These arevery close to the theoretical chlorine content of 10.0 percent. This monochlor wax is substantially free from unchlorinated waxes and polychloro waxes.

Our paraffin hydrocarbons .are preferably obtained from petroleum. Any source of materials,

rich in hydrocarbons of the methane or CnHin-H series, or mixtures relatively rich in these components, may be used ,as starting materialsin practicing our invention. The method of our invention'is particularly applicable to the higher parafiin hydrocarbons but is eminently satisfac- 1 mm on all those hydrocarbons whose monochloro derivatives melt lower than the hydrocarbons themselves. While the product of the preferred embodiment of our invention is a mixture. the monochloro derivatives prepared according to our invention are free from unchiorlnated and more highly chlorinated material. The dichloro derivatives are free from unchlorinated hydrocarbons. monochlorinated hydrocarbons, and more highly chlorinated hydrocarbons. The purity of the final product with respect to homologues is determined by the purity of the starting hydrocarbon. It is understood, of course, that when a pure hydrocarbon is employed, a correspond ingly pure halide is obtained,

Having selected the hydrocarbon in accordance with'the desired final product, we chlorinate the hydrocarbon until approximately that amount of chlorine is absorbed which will produce the monochloro compound when that is the desired product,- or approximately that amount of chicrine which will produce the dichloro compound when that is the desired product, etc.

In the case of parafiin hydrocarbonshaving I from 18 to 24 carbon atoms per molecule; that monochloro waxes are precipitated out nearly quantitatively, while the dichloro and polychloro waxes will remain in solution. 'The precipitated monochloro waxes may be readily separated by settling, filtering, or centrifuging. I

We have also used other crystallization'solvents such as methyl-ethyl ketone, acetone, benzene, acetone-methylene chloride, and various halogenated solvents. The use of a particular one or combination of these solvents requires the experimental determination of the proper proportions and'temperatures necessary to obtain the desired separation of the crude chlorination mixture into the various stages of chlorine contents. Halogenated solvents serve to aid in the precipitation of unchlorinated wax, while benzene increases the solubility of the more highly chlorinated materials.

On further chilling of the solution, or by evaporating off part of the solvent and again chilling, the dichloro and polychloro waxes may be similarly separated.

In this manner, the crude chlorination mixture is, a material having a melting point of approximately F., about 10 percent added chlorine will produce substantially the equivalent of the monochloro product. The amount of chlorination may, vary between 8 percent and 12 percent without being disadvantageous. The percentage of chlorine introduced into the hydrocarbon just described will be approximately 1'7 percent when a dichloro product is desired, The amount of chlorine introduced will be less in the case of the high molecular weight, higher melting hydrocarbons, and more in the case of the lower molecular weight, lower melting hydrocarbons, for

a given number of chlorine atoms per molecule.

The chlorination may be accomplished in any suitable manner. We prefer to heat the hydrocarbon to a temperature at least that of its melting point and pass chlorine gas through the.

melted hydrocarbon. Agitation increases the efficiency of chlorine absorption but is not essential. The chlorination reaction is exothermic and the heat of reaction is ordinarily ample to maintain the-mixture in the liquid state without the addition of other heat. Large quantities of hydrogen chloride gas are evolved which are conducted from the reaction chamber, together with unreacted chlorine. The material ,being ch10 rinated is constantly weighed while the chlorina- I aasaroo 7 tion is in progress, in order to determlne'the extent or chlorination as indicated above. Samples may be removed from time to time, and the speciric gravity of these may be determined in order to follow the chlorination process. If desired, chlorine analyses may be conducted on, samples of the material being chlorinated. After suiiicient chlorine has been introduced, we blow the mixture with air or an inert gas. such as carbon dioxide, until the hydrogen chloride and free chlorine, if any, are substantially removed.

As an example of the manufacture of arch;-

' tively pure chlorinated hydrocarbon, we describe here the manufacture of a relatively pure monochloro wax which contains approximately, 26 carbon atoms per molecule. We started with 723.4 parts of a hydrocarbon wax having amelting point of 120 F. The wax was chlorinated use the chlorine compounds on account of the cheapness and availability of chlorine above all I minute or less to one hour at approximately 200 until 72.5 parts by weight of chlorine had been absorbed. The chlorinated wax was air-blown to remove hydrochloric acid 'anduncombined residual chlorine, and then pressed at 85 F. The

unchlorinated wax was reserved for further chlorination. The liquid portion was then dissolved in acetone, 3 50parts of crude chioro wax being dissolved in 3,226 parts of acetone. The

solution was chilled to minus 18 F. and 185 parts by weight of solid monochloro wax containing 10.3 percent'chlorine was precipitated. Monochlor wax from this paraflin-wax contains theoretically 10.0 percent chlorine. The monochloro wax was normally liquid atroom temperatures. Dichloro waxes and polychioro waxes prepared according to our method are suitable for use in any or the applications described in the prior art, 3 where such dichloro waxesandpoiychloro waxes are required. Since they co'ntainno unchlorinated wax or lower chlorinated waxes, they are particularly efilcient in these applications and-are a distinct improvement ,over the prior art which used crude chlorination mixtures of approximatef ly :the proper chlorine content :but whichconsisted of urichlorinated wax andmore highl chiorinated'wamu 3 i ,While. chlorine has been referred to above almost exclusively, it is to be understood lliatsny oi the halogens are suitable to make'haiogen derivatives 0! the paraflln hydrocarbons according to our method.* Thus bromine, iodine, and fluorine may suitably be used to' obtain the corresponding bromides, iodides and fluorides. For some purposes to which the halides are to be put,

the bromine compounds are much to be desired over the chlorine compounds, since'they are con siderablymore" reactive. Where this is thecase,

we halogenate with bromine, using ahalogen'carrier, such as halides oi antimony, phosphorus,-

iron, various metals,'and the like, and separate thebrominated mixture into its components as described above inthecas'e of the chlorine comr'. to 550 F. A temperature or from 390 F. to

550 is usually satisfactory to: the treatment of chlorinated waxes. At lower temperatures, the action is slower and longer times of heating will be required. At temperatures much higher than 550! F., undersirable side reactions such as cracking and polymerization of the resultant oleilns will occur, and the product isless satisfactory. Under the conditions described, the olefin is formed by the lime removing chlorine from the monochloro compound as hydrogen chloride, which is in turn neutralized by the excess oi lime or driven oil as a gas. A hydrocarbon product containing less than one percent of residual chlorine may be obtained in this manner. Four batches thus, treated resulted in oleflns having chlorine contents of .95, .59, 120, and .09 percents. Bysettling and decanting, by centriiuging, or by filtering, the excess of lime and other solid reaction products may be removed. ,to obtain the oletinic hydrocarbons. The-lime may be washed with a solvent to recover additional oleiins.

In making olefins for some uses, hydrogen chloride may be removed by 'heat-alone.- The color may not be as good, but the chemical characteristics are satisfactory.

The theoretical iodine value im an oleflnic hydrocarbon having the formula CzsHoo is 75.6.

' Actual iodine values for the oleiins obtained from various batches were 74.1, 72.2; and 72.1. The re- -sultant product is an olefin showing reactions pounds. The iodine compounds of the paramn J hydrocarbons may be prepared by. direct iodinadi-, and polyhalogen derivatives may be employed in any step of the process. Thuswe may separate a relatively puremonowor dichloro paramn and convert itto the, corresponding iodine compound, or we 'may convert the crude halogenated mixture into a crude iodinated mixture and then separate into the various stages of haiogenation.

, Fluorine maybe introduced into paraiiln hydrocarbons directly or indirectly by analogous methjdds. For most purpose-at however, ,we meter /to.

tion or by an indirect method, By the rnethod,,the above described separation of mono-,

typical of the general class 01 oleflns.

-In preparing sulphur-bearing derivatives of the higher aliphatic hydrocarbons, we treat chemically the relatively pure halogenated hydrocarbons or their corresponding oleflns. The derivatives and methods. of preparing may be classi-- fled as. follows: f

hydrocarbons from relatively pure halogen- -ated hydrocarbons J A. From mono-halogenated hydrocarbons 1. MercaptansF-Bytreatment with al- I. Sulphur-bearing derivatives of higher paraiiin f kali m'tal hydrosulphides. From these we prepare: 7 Disulphides.-Byoxidation oi captans or mercaptides. 2. sulphides-By treatment with alkali metal sulphides. I From these we prepare:

mer-

G. SillphOIide8.By oxidation or i sulphides.

b. .Sulphonca-By phides.

- kali metal persulphides.

oxidation of sulr 7 w a. Polilsulphidca-By treatment with al- Our relatively pure monohalogenated hydrocarbons may be treated with alkali metal hydrosulphides such as NaSH, readily prepared by saturating aqueous or alcoholic caustic with hydrogen sulphide, to form the high molecular weight mercaptans. For this purpose the bromine compounds are more suitable because of I greater reactivity and ease of replacement than the chlorine compounds.

I Example 1 A solution of 44 parts of caustic soda in 836 parts of water is saturated with hydrogen sulphide gas and then 431 parts of monobrom wax which it is allowed to stand at room temperature for two days. The sulphoxide is precipitated by dilution with twice the volume of water, washed, and dried.

,High molecular weight polysulphides containing as much as -50 percent of chemically combined sulphur are prepared using the polysul phides of the alkali metals.

A great variety of sulphur-bearing, high molecular weight materials may be synthesized by condensing sulphur-bearing compounds having aromatic character with our high molecular weight halogenated hydrocarbons by means or Friedel-Crafts catalysts. Thus We may condense prepared substantially as described above and containing 18 percent bromine is added. The whole is agitated thoroughly while being heated iii an autoclave at 275 F. for eight hours; and then the product is separated, washed, and dried. The wax mercaptan contains eight percent sulphur.

These high mercaptans are interesting and useful in themselves and also serve to :form the disulphides. These are formed by either of two methods: Oxidation of the mercaptan directly as by :nitric acid, or by conversion of the mercantantojthe mercaptide, for example, the lead mercaptide, and treatment of this with sulphur.

Example 2 To 76.8 parts of thewax mercaptan from Example 1 dissolved in 500 parts of light naphtha, we add doctor solution containing 25 parts of lead oxide. The mixture is thoroughly agitated for several hours and then. 3.25 parts of sulphur are added in the usual way. On separating the I naphtha solution and evaporating we obtain our wax disulphide.

The high molecular weight sulphides are similarly formed from the monohalogenated hydrocarbons by the action or alkali metal sulphides.

. From these we may prepare -both sulph-pxides,

R280, and sulphones, R2802. Example 3 We add 120 parts 0180 percent hydrogen peroxide to a solution of 734 parts of our wax sulphide described in Example 2 in 1,000 parts of our monochlor wax, for example, with thiophen-e, thianthrene, and other heterocyclics which corn tain sulphur in a ring and which show aromatic character.

Example 4- and then the mixture is decomposed by poring onto ice and hydrochloric acid. After washing thoroughly to remove aluminum and chloride ions, the solution is dried and evaporated to obtain the alkylated thianthrene.

If our monohalogenated hydrocarbons be'hydrolyzed to the corresponding alcohols, these are useful for various sulphur and oxygen-bearing derivatives of high molecular weight. Esters of these alcohols with sulphur-containing inorganic and organic acids are particularly interesting. By means of thionyl chloride, the alkyl sulphites of the type, R230: may be formed. These when treated with the theoretical quantity of. elemental sulphur are converted into the corresponding thiosulphates, B28203. The higher alcohols'may be used to produce their sulphates through the action of sulphuryl chloride, or chlorosulphonic acid. The sulphates may also be prepared by the oxidation of the corresponding sulphites.

In preparing esters of sulphur containing organic acids, we first prepare the alcohol corresponding to our relatively pure monochlor (or monobrom) wax:

Example 5 Example 6 We add 368 parts of this alcohol to 60 parts of boiling, thionyl= chloride and maintain the temperature of the mixture at 200 F. for five hours. The sulphite is then washed with water and dried.

glacial acetic /acld; The solution warms. after Thiophosphates of the higher alcohols are produced by the action of thiophosphoryl chloride, PSCla. These products are useful addends to lubricants of all sorts.

Example 7 We reflux a mixture of 1,100 parts of the alcohol of, Example 5 with .parts 01' thiophosphoryl chloride in 2,000 parts or xylene for eight The mixture is re-- fluxed until no more hydrogen chloride is evolved tone.

"'"the sameor different carbon atoms. I halogen atoms are on adjacent carbon atoms,

non-,

hours, wash with water, and then dry. On dis.-

tilling oil the xylene, we obtain our higher alkyl- .thiophosphate.

when refluxed with caustic alkalies and carbc bisulphides, the higher alcohols give rise to the alkyl xanthates, for example, ootadecyl xanthate, pentacosyl xanthate, and the like.

7 Example 8 .We pass chlorine into a commercial gradoi most of the unchlorinated hydrocarbon separates.

and is removed by filtration. The filtrate is cooled to -20? I. and the monochlorinated hydrocarbon removed similarly. It is a liquid at I room temperature,

Example 9 We heat at 400 F. in an autoclave, 145 parts 'of the monochlor octadecane, 22 parts of caustic soda, and 200 parts of water at 350 F. for five.

washed,

hours. The octadecanol is separated, and dried.

- Example 10 We dissolve 2'70 parts of octadecanol in 1.000

add 150 parts of carbon bisulphide and heat the mixture at 300 F. under pressure for iourhours. 01100011118, we wash out the sodium octadecyl xanthate with water and evaporate the solution more or less of the oxygen is replaced by sulphur.

parts of nlene and heat with 25 parts of sodium until the latter dissolves. To the solution, we

like, maybe converted into compounds in which Such transformations may be accomplished by heating the'oxygen derivative with phosphorus trisulphide or pentasulphide. Some of these reactions proceed without solvent, but in general it is advantageous to use an inert solvent such as benzene or xylene together with good stirring at a suitable reaction temperature. parent that the solvent must be selected so as'to perature.

Example 11 g Example 12 7 Into 1,000 parts of xylene, we introduce 366 .parts of theketone' of Example 11 and 100 parts of phosphorus trisulphide and boil the mixture for six hours. The solidmaterial is filtered oil! It will be ap-- permit of the use of an adequate reaction temand the xylene distilled from the residualthioke- Alkali metal hydrosulphides act upon the higher dihalogenated paraflln hydrocarbons to form a mixture 01' thioketones and thioglycols, depending on whether the halogen atoms are on Ii" the Vicinal thioglycols will be formed; it on aoncicnoiomnxsn acnsncnsncnH -mm Vicinal thioglyco R.CIICI.CH.CHCI.CH:+2KSH acnsncmcnsmcmwxm I Disioined thioglyool The process is identical with that of Example 1. Waxy resins may be produced by the action of sulphur dioxide on our high molecular weight oleflns. The reaction is advantageously catalyzed by nitric acid and various nitrates including lithium, ammonium, and silver nitrates. Perchlorates and perchloric acid are also effective catalysts. Generally the product represents equlmolecular proportions of sulphur dioxide and 4 olefin condensed together into molecular aggregates 01 as high as 300,000. These resins are thermoplastic and promise great usefulness. Furthermore, it is possible, to produce by this means, oil-soluble materials which are useful for blending in lubricants.

' Y Example 13 A mixture of 5 partsof ammonium nitrate and 350 parts of the wax olefin prepared substantially as described above were sealed in a bomb with sulphur dioxide under 50 pounds pressure. The bomb was heated at 210 F. for 50 hours. The bomb contents were allowed to cool and the'pres sure released. The product is a waxy resin of high molecular weight.

It is to be understood that any or all of the lies primarily in a method of obtaining high molecular weight 'sulpl'uir compounds in a relatively pure state as defined and described above and we do not wish to claim the old processes. However we dowish to claim all novelty inherent in our processes as broadly as permits. l It will be seen that we have accomplished the the state of the art' I purpose of ourinvention; namely, to provide relatively pure sulphur-bearing derivatives of high molecular weight parafiln hydrocarbons, each substantially free from other types of sulphur compounds and from unreacted paraflin hydrocarbons. Y

It will be understood that certain features and subcombinations are of utility and may be em- Having thus described our invention, we claim:

1. A method for the synthesis of sulphur-bearing derivatives of-high molecular weight, including the steps or halogenatins' parafhnie hydro-' carbons whose monochloro derivatives melt lower than the hydrocarbons themselves, separating a relatively pure halogenated hydrocarbon from. the crude halogenated mixture, and replacing the halogen of said relatively pure halogenated hydrocarbon with a sulphur-bearing group by means of a sulphur-bearing reagent selected from the class consisting of alkali metal hydrosulphides, alkali metal sulphides, alklai metal polysulphides.

2. A method of synthesizing sulphur-bearing hydrocarbon derivatives of high molecular weight, including the steps of halogenating par- 

